Seafood study finds plastic in all samples

Date:
August 12, 2020
Source:
University of Exeter
Summary:
A study of five different seafoods has found traces of plastic in
every sample tested.



FULL STORY ==========================================================================
A study of five different seafoods has found traces of plastic in every
sample tested.


========================================================================== Researchers bought oysters, prawns, squid, crabs and sardines from a
market in Australia and analysed them using a newly developed method
that identifies and measures five different plastic types simultaneously.

The study -- by the University of Exeter and the University of Queensland
- - found plastic levels of 0.04 milligrams (mg) per gram of tissue
in squid, 0.07mg in prawns, 0.1mg in oysters, 0.3mg in crabs and 2.9mg
in sardines.

"Considering an average serving, a seafood eater could be exposed
to approximately 0.7mg of plastic when ingesting an average serving
of oysters or squid, and up to 30mg of plastic when eating sardines, respectively," said lead author Francisca Ribeiro, a QUEX Institute
PhD student.

"For comparison, 30mg is the average weight of a grain of rice.

"Our findings show that the amount of plastics present varies greatly
among species, and differs between individuals of the same species.



========================================================================== "From the seafood species tested, sardines had the highest plastic
content, which was a surprising result." Co-author Professor Tamara
Galloway, of Exeter's Global Systems Institute, said: "We do not fully understand the risks to human health of ingesting plastic, but this new
method will make it easier for us to find out." The researchers bought
raw seafood -- five wild blue crabs, ten oysters, ten farmed tiger prawns,
ten wild squid and ten wild sardines.

They then analysed them for the five different kinds of plastics that
can be identified by the new method.

All of the plastics are commonly used in plastic packaging and synthetic textiles and are frequently found in marine litter: polystyrene,
polyethylene, polyvinyl chloride, polypropylene and poly(methyl
methacrylate).



==========================================================================
In the new method, edible tissues are treated with chemicals to dissolve
the plastics present in the samples. The resulting solution is analysed
using a highly sensitive technique called Pyrolysis Gas Chromatography
Mass Spectrometry which can identify the different kinds of plastic in
the sample at the same time.

Polyvinyl chloride was found in all samples, while the plastic found in
highest concentrations was polyethylene.

Microplastics are very small pieces of plastic that pollute much of the
planet, including the sea where they are eaten by marine creatures of
all types, from small larvae and planktonic organisms to large mammals.

Studies to date show that microplastics not only enter our diet from
seafood, but also from bottled water, sea salt, beer and honey, as well
the dust that settles on our meals.

The new testing method is a step towards defining what microplastic
levels can be considered harmful and assessing the possible risks of
ingesting microplastics in food.


========================================================================== Story Source: Materials provided by University_of_Exeter. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Francisca Ribeiro, Elvis D. Okoffo, Jake W. O'Brien, Sarah
Fraissinet-
Tachet, Stacey O'Brien, Michael Gallen, Saer Samanipour,
Sarit Kaserzon, Jochen F. Mueller, Tamara Galloway, Kevin
V. Thomas. Quantitative Analysis of Selected Plastics in
High-Commercial-Value Australian Seafood by Pyrolysis Gas
Chromatography Mass Spectrometry. Environmental Science &
Technology, 2020; 54 (15): 9408 DOI: 10.1021/acs.est.0c02337 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200812144104.htm

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